Novel Effective Bacillus cereus Group Species “ Bacillus clarus ” Is Represented by Antibiotic-Producing Strain ATCC 21929 Isolated from Soil

Abstract

The B. cereus group comprises numerous closely related lineages with various degrees of pathogenic potential and industrial relevance. Species-level taxonomic classification of B. cereus group strains is important for risk evaluation and communication but remains challenging. Biochemical and phenotypic assays are often used to assign B. cereus group strains to species but are insufficient for accurate taxonomic classification on a genomic scale. Here, we show that antibiotic-producing ATCC 21929 represents a novel lineage within the B. cereus group that, by all metrics used to delineate prokaryotic species, exemplifies a novel effective species. Furthermore, we show that ATCC 21929 is incapable of producing enterotoxins Hbl and Nhe or exhibiting cytotoxic effects on HeLa cells at human body temperature in vitro . These results provide greater insight into the genomic and phenotypic diversity of the B. cereus group and may be leveraged to inform future public health and food safety efforts.